Novel intermetallic-reinforced near-α Ti alloys manufactured by spark plasma sintering

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:792

Article

Wimler, David¹  Lindemann, Janny²  Gammer, Christoph³  Spoerk-Erdely, Petra¹  Stark, Andreas⁴  Clemens, Helmut¹  Mayer, Svea¹ 

[1] Univ Leoben, Dept Mat Sci, Roseggerstr 12, A-8700 Leoben, Austria

[2] GfE Fremat GmbH, Gewerbegebiet Sud 20, D-09618 Brand Erbisdorf, Germany

[3] Austrian Acad Sci, Erich Schmid Inst Mat Sci, Jahnstr 12, A-8700 Leoben, Austria

[4] Helmholtz Zentrum Geesthacht, Inst Mat Res, Max Planck Str 1, D-21502 Geesthacht, Germany

关键词: Spark plasma sintering;    Near-alpha alloy;    alpha(2)-Ti3Al;    Metal matrix composite;    Microstructure;    Mechanical properties;   

DOI  :  10.1016/j.msea.2020.139798

来源: Elsevier

【 摘 要 】

Near-alpha Ti alloys are ideal candidates for high-temperature aerospace, automotive and nautical propulsion systems due to their high strength, low density and good corrosion resistance. However, the maximum service temperature of the well-known near-alpha alloy Ti6242S is limited to about 540 degrees C. By adding, for example, intermetallic gamma-TiAl based alloy particles to Ti6242S powder a significant increase in yield strength up to 650 degrees C can be achieved by means of spark plasma sintering, along with sufficient room temperature ductility. In this study, investigations on the underlying strengthening mechanisms were carried out. For this purpose, mechanical tests and detailed microstructural characterization were performed. Spark plasma sintering at 1150 degrees C of powder blends with 10 m.% spherical gamma-TiAl based powder (<20 mu m) leads to a homogeneous dissolution of the TiAl particles in the matrix material and a refinement of the lamellar microstructure. Due to the formation of ordered intermetallic alpha(2)-Ti3Al precipitates, which are completely stable up to 670 degrees C in the newly evolved Ti-8.3Al-1.8Sn-3.7Zr-2.0Mo-0.9Nb-0.08Si alloy (m.%), the creep resistance at 600 degrees C has been increased significantly. In the B containing variant, it was found that finely distributed titanium borides TiB formed in the Ti6242 matrix and led to an even more pronounced refinement of the microstructure. For B additions of 1 m.%, however, the creep resistance at 600 degrees C is reduced compared to the other alloys, but the strength is increased up to 500 degrees C.

【 授权许可】

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